ARC SUPPRESSOR This invention relates generally to are chutes or are suppressors for multipole electric safety switches, and more particularly to an arc suppressor including cold-molded arc-suppressive material which supports a plurality of metal plates in spaced relationship and also completely covers the surface of the plate nearest the origin of the are on the side thereof facing the arc origin.

In the drawings, FIG. 1 is a front elevational view of one pole portion of a multipole fusible safety switch including an arc suppressor constructed in accordance with this invention;

FIG. 2 is a sectional view taken along the line 22 of FIG. 1;

FIG. 3 is a sectional view taken along the line 3--3 of FIG. 1;

FIG. 4 is a fragmentary sectional view taken generally along the line 4-4 ofFIG. 1;

FIG. 5 is a fragmentary sectional view of the structure of FIG. 1 taken along the line 5-5 of FIG. 4; and

FIG. 6 is a sectional view taken along the line 6-6 of FIG. 3.

The drawings illustrate a single pole portion of a multipole fusible safety switch similar to that disclosed in US. Pat. No. 3,339,047, issued Aug. 29, I967. A base 10 molded ofinsulating material is securable to the rear wall of an enclosure (not shown). Secured to the base 10 by a pair of screws 12, only one of which is shown in FIG. 4, is a terminal strap 14 which includes a rear platform 14a and a front platform 14b joined by a connecting portion 140 (FIG. 3).

A relatively large connector including a stepped body 16 (FIGS. 1 and 3) having a pair of clamping screws 18 threadedly mounted therein is secured to the front platform 14b by a bolt 19 and a nut 20. Further, a relatively small connector including a stepped body 22 having a clamping screw 24 threadedly mounted therein is secured to the platform 14b by a bolt 25 and a nut 26. The two connectors are provided because a single wire cable large enough to carry the current for which the switch is designed would be too stiff and unwieldy. The bolts 19 and 25 are held captive in the platform 14b by a pin 28 disposed in the connecting portion 14c, the heads of the bolts being disposed between the pin 28 and the platform 14b. Further, the bolts 19 and 25 are disposed on opposite sides of the connecting portion 14c and a flat surface on the head of each bolt abuts an adjacent surface of the connecting portion 140 to prevent rotation of the bolts.

A stationary contact assembly including a double jaw member 30 (FIGS. 3 and 4) and a contact pressure spring member 32 is secured to the rear platform 1411 by a bolt 33 and a nut 34, the head of the bolt 33 being recessed within the base 10. A hoodlike casing 36 molded of insulating material is secured on one side to the rear platform 14a by a screw 37 (FIG. 3) and on the other side to the base 10 by a pair of screws 38 (FIGS. 1 and 3).

Secured within the casing 36 are a pair of complementary support members 40 and 41 formed of cold-mold, arc-suppressive insulating material such as melamine bonded oxides or hydrates of aluminum or magnesium. A pair of screws 42 and 43 and cooperating nuts 44 and 45 secure the support members 40 and 41 respectively to opposite sidewalls of the casing 36. In addition, the casing 36 is provided with a pair of projections 36a and 36b (FIGS. 5 and 6) which extend into appropriate recesses respectively in the support members 40 and 41. Adjacent the front end, the upper wall of the casing 36 is provided with a series of vent holes 360. A plurality of generally U-shaped metal plates 48 are mounted in spaced relationship in complementary grooves provided in the support members 40 and 41.

Also secured to the base 10 by a pair of screws 50 (FIG. 4) is a combination fuse and switch blade mounting means including a pair of aligned generally U-shaped spring members 52 (FIGS. 1 and 2), a generally U-shaped mounting member 54 disposed within the spring members 52, a generally L- shaped mounting member 56 disposed within the mounting member 54, and an anchoring plate 58 into which the screws 50 are threaded to secure the members 52, 54, and 56 to the base 10. A pin 60 is mounted adjacent one end in the member 56 and adjacent the other end in one leg portion of the member 54. A switch blade 62, movable by blade actuating means not shown, is pivotally mounted on the pin 60. The end portion of the pin 60 mounted in the one leg portion of the member 54 is larger in diameter than the remainder thereof and is trapped between the switch blade 62 and one leg portion of one of the spring members 52 to prevent axial movement of the pin. A spacer 64 is mounted between the member 56 and the one leg portion of the member 54 adjacent the other end of these members from the pin 60. The space 64 may have a smaller diameter portion (not shown) projecting into either the member 56 or the member 54. Before being secured to the base 10 by the screws 50, the assembly including the members 52, member 54, member 56, anchoring plate 58, pin 60, switch blade 62, and spacer 64 is secured together by a pair of screws 66 also threaded into the anchoring plate 58.

Another base 68 (FIG. 1) molded of insulating material is securable to the rear wall of the enclosure (not shown) in spaced relationship to the base 10. Secured to the base 68 is a terminal strap 70 similar to the terminal strap 14 and having connector bodies identical to bodies 16 and 22 secured to the front platform thereof. A fuse clip 72 reinforced by a spring member 74 is secured to the rear platform of the terminal strap 70. A fuse 76 having blade terminals adjacent opposite ends is shown with one blade terminal mounted in the fuse clip 72 and the other blade terminal mounted between the member 56 and the other leg portion of the member 54.

As shown in FIGS. 3 and 4, the support members 40 and 41 respectively include portions 400 and 41a disposed above the jaw member 30 and extending rearwardly of the front end thereof, where any are would originate upon separation of the switch blade 62 from the jaw member 30.

Further, as shown in FIGS. 4 and 6, the support members respectively include portions 40b and 41b which together substantially completely cover the plate 48 nearest the jaw member 30 on the side of the plate facing the jaw member. In addition, as shown in FIGS. 4 and 5, the support members respectively include portions 400 and 41c which support the plates 48 in spaced relationship and respectively line opposite walls of the casing 36. The construction and arrangement result in an arc suppressor which can repeatedly withstand interruption of larger currents than formerly possible with an arc suppressor of similar size.

Iclaim:

1. In a switch having a stationary contact jaw member cooperable with a pivotable switch blade, an arc suppressor comprising a hoodlike casing secured in covering relationship to the jaw member and having an open side facing the switch blade, a pair of complementary cold-molded arc-suppressive insulating support members secured respectively to a pair of opposed side walls of the casing, and a plurality of generally U-shaped, flat, metal plates held by the support members in spaced-apart relationship forwardly of the jaw member, each of the support members having a covering portion covering substantially one-half of the metal plate nearest the jaw member on the side thereoffacing the jaw member.

2. An arc suppressor as claimed in claim 1 wherein each of the support members lines one of the pair of opposed sidewalls of the casing at the end thereof opposite the jaw member.

3. An arc suppressor as claimed in claim 1 wherein each of the support members has a portion extending from an upper end of the covering portion which covers half the metal plate nearest the jaw member, lining a portion of an upper wall of the casing opposite the open side, and extending rearwardly of the front end of the jaw member.

4. An arc suppressor as claimed in claim 1 wherein each of the support members has a portion extending in a direction away from the jaw member from a lower end portion which covers half the metal plate nearest the jaw member, and covering the lower edge portions of one leg portion of each of the generally U-shaped metal plates.